cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A097190 Triangle read by rows in which row n gives coefficients of polynomial R_n(y) that satisfies R_n(1/3) = 9^n, where R_n(y) forms the initial (n+1) terms of g.f. A097191(y)^(n+1).

Original entry on oeis.org

1, 1, 24, 1, 36, 612, 1, 48, 1104, 15912, 1, 60, 1740, 32130, 417690, 1, 72, 2520, 56700, 912492, 11027016, 1, 84, 3444, 91350, 1750014, 25562628, 292215924, 1, 96, 4512, 137808, 3059856, 52303968, 710025264, 7764594552, 1, 108, 5724, 197802, 4992354
Offset: 0

Views

Author

Paul D. Hanna, Aug 03 2004

Keywords

Examples

			Row polynomials evaluated at y=1/3 equals powers of 9:
9^1 = 1 + 24/3;
9^2 = 1 + 36/3 + 612/3^2;
9^3 = 1 + 48/3 + 1104/3^2 + 15912/3^3;
9^4 = 1 + 60/3 + 1740/3^2 + 32130/3^3 + 417690/3^4;
where A097191(y)^(n+1) has the same initial terms as the n-th row:
A097191(y) = 1 + 12y + 60y^2 + 90y^3 - 558y^4 - 2916y^5 + 2160y^6 +...
A097191(y)^2 = 1 + 24y +...
A097191(y)^3 = 1 + 36y + 612y^2 +...
A097191(y)^4 = 1 + 48y + 1104y^2 + 15912y^3 +...
A097191(y)^5 = 1 + 60y + 1740y^2 + 32130y^3 + 417690y^4 +...
Rows begin with n=0:
  1;
  1, 24;
  1, 36,  612;
  1, 48, 1104,  15912;
  1, 60, 1740,  32130,  417690;
  1, 72, 2520,  56700,  912492, 11027016;
  1, 84, 3444,  91350, 1750014, 25562628, 292215924;
  1, 96, 4512, 137808, 3059856, 52303968, 710025264, 7764594552; ...
		

Crossrefs

Programs

  • Mathematica
    Table[SeriesCoefficient[3*y/((1-27*x*y) + (3*y-1)*(1-27*x*y)^(8/9)), {x, 0,n}, {y,0,k}], {n,0,12}, {k,0,n}]//Flatten (* G. C. Greubel, Sep 17 2019 *)
  • PARI
    {T(n,k)=if(n==0,1,if(k==0,1,if(k==n, 3^n*(9^n-sum(j=0,n-1, T(n,j)/3^j)), polcoeff((Ser(vector(n,i,T(n-1,i-1)),x) +x*O(x^k))^((n+1)/n),k,x))))}

Formula

G.f.: A(x, y) = 3*y/((1-27*x*y) + (3*y-1)*(1-27*x*y)^(8/9)).
G.f.: A(x, y) = A097192(x*y)/(1 - x*A097193(x*y)).